Constant temperature gas/liquid mixture generating system for use in wafer drying process

ABSTRACT

A constant temperature gas/liquid mixture generating system for using in wafer drying process includes: an interior tank; a first liquid supplying device for supplying liquid IPA to the interior tank; a gas supplying device for supplying nitrogen to the interior tank; an exhausting device for exhausting IPA and nitrogen mixture from said constant temperature gas/liquid mixture generating system; an exterior tank, surrounding the interior tank; a second liquid supplying device for supplying a second liquid to the exterior tank; a temperature control device for controlling the second liquid to be within a desired temperature range; and a draining device for draining the second liquid out of the exterior tank.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a system for use in wafer drying process, and more particularly to a constant temperature gas/liquid mixture generating system for safely heating and generating a gas/liquid mixture for wafer drying process.

2. Description of the Prior Art

In a wafer drying process, one of wafer drying techniques utilizes an inert gas, such as nitrogen (N₂), mixed with an organic solvent, such as isopropyl alcohol (IPA) vapor cloud. The above mixture is heated to its boiling point and the generated vapors are used for drying the wafer. As the generated vapors contacts the wafer, the residual pure water or water vapor adhering thereto from wafer rinsing step may be displaced by the vapors and then the IPA is evaporated by the heated N₂ to dry the wafer.

A Kimmon device, which is being extensively used at present, utilizes the aforementioned principle that an organic solvent IPA is boiled and heated over 200° C. and residual pure water or water vapor on the surface of a wafer is displaced by the IPA vapor, followed by introducing heated N₂ to evaporate liquid IPA and dry the wafer. Since IPA is a flammable liquid, the risk of a fire hazard is a safety concern while operating the aforementioned device.

Taiwan patent publication number 200714843, filed by Tokyo Electron Limited, disclosed a method of drying by using vapor and the device thereof. The device mixes a liquid IPA with N₂ within a mix chamber first, and then sends the N₂/IPA mixture to a vapor generating device to be heated, so as to generate the vapor for using in wafer drying process. A light energy source is used as a heating source of the vapor generating device, which substantially comprises a container body, a halogen lamp, a thermal insulation material and a spiral tube. Although the aforementioned device may moderately heat the N₂/IPA mixture, the cost is relatively high because of the complex structure.

In order to resolve the safety issue related to the gas generating equipment for drying wafer of prior art, the present invention provides a system and a constant temperature gas/liquid mixture generating system for use in wafer drying process.

SUMMARY OF THE INVENTION

To resolve the aforementioned issues, a constant temperature gas/liquid mixture generating system for use in a wafer drying process is proposed, which is used to heat and generate a gas/liquid mixture for use in a wafer drying process.

The present invention is also directed to a system for use in wafer drying process, which utilizes the gas/liquid mixture to dry wafers.

The present invention is directed to a constant temperature gas/liquid mixture generating system for use in wafer drying process including a water bath for heating a N₂/IPA mixture to a desired temperature.

The present invention is also directed to a constant temperature gas/liquid mixture generating system for use in wafer drying process, which may heat and generate a gas/liquid mixture under a safe operating condition.

The present invention is also directed to a system for use in wafer drying process, which may dry wafer in a safe and stable environment.

In one embodiment, the proposed constant temperature gas/liquid mixture generating system for use in wafer drying process includes an interior tank, a first liquid supplying device, a gas supplying device, an exhausting device, an exterior tank, a second liquid supplying device, a temperature control device and a draining device. The first liquid supplying device is used to supply a first liquid to the interior tank, wherein the first liquid comprises liquid IPA. The gas supplying device supplies a gas into the interior tank, wherein the gas comprises N₂. The gas is mixed with the first liquid to form a gas/liquid mixture (IPA+N₂). The gas supplying device further comprises a gas inlet and a bottom gas injection device, wherein the bottom gas injection device is connected to the gas inlet for injecting the gas from the bottom of the interior tank towards the top of the interior tank. The bottom gas injection device is substantially disposed on the bottom of the interior tank and comprises at least one injection hole. The exhausting device is used to exhaust the gas/liquid mixture from the constant temperature gas/liquid mixture generating system for use in wafer drying process. The exterior tank surrounds the interior tank. The second liquid supplying device supplies a second liquid into the exterior tank and in contact with the interior tank. The temperature of the second liquid is maintained at higher than room temperature. The temperature control device is used to control the temperature of the second liquid within a predetermined temperature range of 45° C. to 80° C. The exterior tank further comprises a partitioning plate for defining a flow path of the second liquid. The draining device is used to drain the second liquid out of the exterior tank.

In one embodiment, the constant temperature gas/liquid mixture generating system for use in wafer drying process may further comprise a liquid level detecting device disposed in the interior tank for measuring the level of the first liquid, wherein the liquid level detecting device may be a floating type. A temperature measuring device is used to measure the temperature of the second liquid.

A system for use in wafer drying process according to the present invention includes a liquid tank, a gas tank, a constant temperature gas/liquid mixture generating device and a wafer drying device. The liquid tank is used to store and supply a first liquid, wherein the first liquid comprises liquid IPA. The gas tank is used to store and supply a gas, wherein the gas comprises N₂. The constant temperature gas/liquid mixture generating device is connected to the liquid and gas tanks. The first liquid and the gas are mixed to form a gas/liquid mixture. The constant temperature gas/liquid mixture generating device comprises: an interior tank, a first liquid supplying device, a gas supplying device, an exhausting device, an exterior tank, a second liquid supplying device, a temperature control device and a draining device. The wafer drying device is connected to the constant temperature gas/liquid mixture generating device.

The wafer drying device further comprises a wafer drying chamber comprising at least one nozzle port. The system for wafer drying further comprises a gas transporting device for transporting the gas/liquid mixture from the constant temperature gas/liquid mixture generating device to the wafer drying chamber. The gas transporting device is connected to the nozzle port for supplying the gas/liquid mixture to the wafer drying chamber to dry the wafer.

Compared with a wafer drying device of the prior art, advantages of the present invention are listed below. First, the constant temperature gas/liquid mixture generating system for use in wafer drying process comprises an internal tank and an external tank, the exterior tank surrounds the interior tank and the second liquid circulating therein maintained at a range of 45° C.-80° C. may serve as a liquid bath for heating the gas/liquid mixture (IPA+N₂) in the interior tank. Thus, the temperature of the gas/liquid mixture can be effectively maintained at a desired temperature. Secondly, the system for use in wafer drying is integrated with the aforementioned constant temperature gas/liquid mixture generating system, and because the temperature of the gas/liquid mixture is maintained at a comparatively lower temperature and heated by a water bath, and therefore there is no need to install any explosion prevention device as in the case of the prior art, which would not only reduce the cost but may also resolves the safety concern.

The objective, technologies, features and advantages of the present invention will become apparent from the following description in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing conceptions and their accompanying advantages of this invention will become more readily appreciated after being better understood by referring to the following detailed description, in conjunction with the accompanying drawings, wherein:

FIG. 1 is a perspective view illustrating a constant temperature gas/liquid mixture generating system for use in wafer drying process according to one embodiment of the present invention;

FIG. 2 is a perspective view illustrating a separation plate of a constant temperature gas/liquid mixture generating system for use in wafer drying process including partitioning plate for defining the flow path of a second liquid according to one embodiment of the present invention; and

FIG. 3 is a schematic view illustrating main devices and structure of a system for use in wafer drying process according to one embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The detailed explanation of the present invention is described as following. The described preferred embodiments are presented for purposes of illustrations and description, and they are not intended to limit the scope of the present invention.

Referring to FIG. 1 and FIG. 2, in one embodiment of the constant temperature gas/liquid mixture generating system 100 for use in wafer drying process includes a interior tank 110, a first liquid supplying device 120, a gas supplying device 130, an exhausting device 140, an exterior tank 150, a second liquid supplying device 160, a temperature control device 170 and a draining device 180.

The first liquid supplying device 120 supplies a first liquid L1 into the interior tank 110, wherein the first liquid L1 comprises liquid isopropyl alcohol (IPA).

The gas supplying device 130 supplies a gas G1 into the interior tank 110, wherein the gas G1 comprises nitrogen (N₂). The first liquid L1 and the gas G1 are mixed in the interior tank 110 to form a gas/liquid mixture G2 (IPA+N₂) which may be used for drying a wafer 1.

The gas supplying device 130 comprises a gas inlet 132 and a bottom gas injection device 134. The bottom gas injection device 134 is connected to the gas inlet 132 and is adopted for injecting the gas G1 from the bottom towards top of the interior tank 110. The bottom gas injection device 134 is disposed at the bottom of the interior tank 110 and comprises at least one injection hole 136.

The exhausting device 140 is used to exhaust the gas/liquid mixture G2 from the constant temperature gas/liquid mixture generating system 100 for use in wafer drying process.

The exterior tank 150 surrounds the interior tank 110. The second liquid supplying device 160 supplies a second liquid L2 into the exterior tank 150 such that the second liquid contacts and surrounds the interior tank 110. The temperature of the second liquid L2 is maintained at higher than room temperature. The second liquid L2 may be processed industrial water. The temperature control device 170 heats and controls the temperature of the second liquid L2 within a predetermined temperature range, for example but limited to, about 45° C. to 80° C.

The exterior tank 150 comprises at least one partitioning plate 152 for defining a flow path of the second liquid L2. During the operation of the constant temperature gas/liquid mixture generating system 100, the second liquid L2 is continuously circulated along the flow path defined by the partitioning plate 152. The draining device 180 is used to drain the second liquid L2 out of the exterior tank 150.

The constant temperature gas/liquid mixture generating system 100 for use in wafer drying process may further comprise a liquid level detecting device 112 disposed in the interior tank 110 for measuring the level of the first liquid L1, wherein the liquid level detecting device 112 may be a floating type; and a temperature measuring device 154 may be adopted to measure the temperature of the second liquid L2. The liquid level detecting device 112 may be adopted for facilitating a continuous supply of the first liquid L1 so as to maintain a constant predetermined range of volume of the first liquid L1 within the interior tank 110.

Referring to FIG. 1, FIG. 2 and FIG. 3, in one embodiment, a system 300 for use in wafer drying process includes a liquid supplying device 310, a gas supplying device 320, a constant temperature gas/liquid mixture generating device 100, a gas transporting device 330 and a wafer drying device 200.

The liquid tank 310 stores and supplies the first liquid L1 to the interior tank 110 via the first liquid supplying device 120.

The gas tank 320 stores and supplies the gas G1 into the interior tank 100 via the gas supplying device 130.

The constant temperature gas/liquid mixture generating device 100 is connected to the liquid supplying device 310. As described above, the first liquid L1 and the gas G1 are mixed in the interior tank 110 to form a gas/liquid mixture G2, and the mixture G2 is heated and maintained at a predetermined temperature, which is higher than room temperature. The gas/liquid mixture G2 is heated and transported into the wafer drying device 200 and used for drying the wafer 1.

The gas transporting device 330 is connected to the exhausting device 140. The wafer drying device 200 comprises a wafer drying chamber 210. The wafer drying chamber 210 comprises a nozzle port 212 which is connected to the gas transporting device 330 to receive the gas/liquid mixture G2 for drying the wafer 1.

In order to safely heat the gas/liquid mixture G2, the gas/liquid mixture G2 is not directly heated to its boiling point as in the case of the prior art, instead it is heated by the second liquid L2 that surrounds the interior tank 110 and serves as a water bath and at a comparatively lower temperature. The second liquid L2 is heated and controlled by the temperature control device 170 at a temperature range of about 45° C.-80° C. The temperature of the second liquid L2 in the exterior tank 150 is measured by a temperature measuring device 154. The second liquid L2 is circulated along a flow path defined by at least one partitioning plate 152; and the second liquid L2 in the exterior tank 150 may be drained out of the exterior tank 150 by a draining device 180. The drained out second liquid L2 may be recycled for use in other factory operation.

After the gas/liquid mixture G2 is heated to a desired temperature, the gas/liquid mixture G2 is exhausted from the constant temperature gas/liquid mixture generating device 100 by the exhausting device 140 and transported to the wafer drying chamber 210 of the wafer drying device 200 via the gas transporting device 330 and the nozzle port 212 of the wafer drying chamber 210 for drying the wafer 1. The aforementioned system for use in wafer drying process and the constant temperature gas/liquid mixture generating system may safely heat the gas/liquid mixture G2 without the need for installing any explosion prevention device. Thus, this not only reduces the cost but also promotes the safety for the operators.

While the invention is susceptible to various modifications and alternative forms, a specific example thereof has been shown in the drawings and is herein described in detail. It should be understood, however, that the invention is not to be limited to the particular form disclosed, but to the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the appended claims. 

1. A constant temperature gas/liquid mixture generating system for use in wafer drying process, comprising: an interior tank; a first liquid supplying device, for supplying a first liquid into said interior tank; a gas supplying device, for supplying a gas into said interior tank, wherein said gas is mixed with said first liquid in said interior tank to form a gas/liquid mixture; an exhausting device, for exhausting said gas/liquid mixture from said constant temperature gas/liquid mixture generating system; an exterior tank, surrounding said interior tank; a second liquid supplying device, for supplying a second liquid into said exterior tank, wherein said second liquid contacts and surrounds the interior tank; a temperature control device, for controlling a temperature of said second liquid at a predetermined temperature range; and a draining device, for draining said second liquid out of said exterior tank.
 2. A constant temperature gas/liquid mixture generating system for use in wafer drying process according to claim 1, wherein said gas supplying device further comprises: a gas inlet; and a bottom gas injection device, connected to said gas inlet for injecting said gas from a bottom of said interior tank toward a top of said interior tank.
 3. A constant temperature gas/liquid mixture generating system for use in wafer drying process according to claim 2, wherein said bottom gas ejecting device comprises at least one gas injection hole.
 4. A constant temperature gas/liquid mixture generating system for use in wafer drying process according to claim 2, wherein said bottom gas ejecting device is substantially disposed on a bottom of said interior tank.
 5. A constant temperature gas/liquid mixture generating system for use in wafer drying process according to claim 1, wherein said gas supplying device supplies nitrogen (N₂).
 6. A constant temperature gas/liquid mixture generating system for use in wafer drying process according to claim 1, wherein said first liquid comprises a liquid isopropyl alcohol (IPA).
 7. A constant temperature gas/liquid mixture generating system for use in wafer drying process according to claim 1, further comprising a liquid level detecting device disposed in said interior tank.
 8. A constant temperature gas/liquid mixture generating system for use in wafer drying process according to claim 7, wherein said liquid level detecting device may be a floating type.
 9. A constant temperature gas/liquid mixture generating system for use in wafer drying process according to claim 1, wherein temperature of said second liquid in said exterior tank is higher than room temperature.
 10. A constant temperature gas/liquid mixture generating system for use in wafer drying process according to claim 1, wherein said predetermined temperature range is within 45° C. to 80° C.
 11. A constant temperature gas/liquid mixture generating system for use in wafer drying process according to claim 1, wherein said second liquid comprises processed industrial water.
 12. A constant temperature gas/liquid mixture generating system for use in wafer drying process according to claim 1, further comprising a temperature measuring device for measuring temperature of said second liquid.
 13. A constant temperature gas/liquid mixture generating system for use in wafer drying process according to claim 1, wherein said exterior tank further comprises a partitioning plate for defining a flow path of said second liquid.
 14. A system for use in wafer drying process, comprising: a liquid tank, for storing a first liquid; a gas tank, for storing a gas; a constant temperature gas/liquid mixture generating device, comprising: an interior tank, for receiving and mixing said first liquid stored in said liquid tank via a liquid supplying device and said gas stored in said gas tank via gas supplying device to form a gas/liquid mixture; an exterior tank, surrounding said interior tank; a second liquid supplying device, for supplying a second liquid into said exterior tank, wherein said second liquid surrounds said interior tank; a temperature control device, for controlling a temperature of said second liquid within a predetermined temperature range; and a wafer drying device, connected to said interior tank for receiving heated gas/liquid mixture for drying a wafer.
 15. A system for using in wafer drying process according to claim 14, further comprising an exhausting device for exhausting said gas/liquid mixture from said constant temperature gas/liquid mixture generating system.
 16. A system for using in wafer drying process according to claim 14, further comprising a draining device for draining said second liquid out of said exterior tank.
 17. A system for using in wafer drying process according to claim 14, wherein said first liquid comprises a liquid isopropyl alcohol (IPA).
 18. A system for using in wafer drying process according to claim 14, wherein said gas comprises nitrogen (N₂).
 19. A system for using in wafer drying process according to claim 14, wherein said wafer drying device comprises comprising a wafer drying chamber.
 20. A system for using in wafer drying process according to claim 19, further comprising a gas transporting device for transporting said gas/liquid mixture from said constant temperature gas/liquid mixture generating device to said wafer drying chamber.
 21. A system for using in wafer drying process according to claim 20, wherein said wafer drying chamber comprises at least one nozzle port connected to said gas transporting device for supplying said gas/liquid mixture to said wafer drying chamber to dry wafer.
 22. A system for using in wafer drying process according to claim 14, wherein said predetermined temperature is higher than room temperature. 